Sebastian wrote about what's happening for Plasma next in his latest blog post. He began with, "In the past week, we hit something that really feels like a milestone in Plasma development. Plasma 2 has become somewhat usable, at least if your pain level is high enough. It occurred to me after I realized after a few hours of using it that the workspace shell running on my laptop was not actually the current stable release of Plasma, but the development version."
KDE developers are making good progress with Qt Quick, the performance is doing very good with Qt 5.2, and the KDE Frameworks 5 momentum of modularizing the software stack is working out. Porting applications to use KDE Frameworks 5 is mostly about changes to the build system, any Qt5 porting needed, and a few API changes. Moving to the new frameworks architecture is not nearly as invasive as the changes in going from KDE3 to KDE4.
KDE developers are still hoping to ship their first technology preview of Frameworks 5 and Plasma 2 in December of this year followed by stable releases in 2014.